hi.
my truck runs pretty well considering it has 185k. it has a rough idle, which may or may not contribute to this problem: it accelerates fine until it warms up, then if i step on it to pass someone or merge onto the interstate, it falls on its face somewhere between 3 and 4000 rpms. it does the same if i set the cruise on a 70 mph highway and encounter a hill. it seems to be getting worse. the plugs arent new, but i inspected all 6 and they look good. i also know they have around 20k highway miles on them. i tested the coil and found a bad post, so i replaced it with no change in the symptoms. i also just changed the fuel filter a couple days ago...no change there either. theres no engine light on, ive been thinking of unplugging a sensor just to turn it on so advance will scan the codes. so ive got a rough idle (which doesnt really bother me) and a hard stall under heavy acceleration when warm. any ideas?

hi. my truck runs pretty well considering it has 185k. it has a rough idle, which may or may not contribute to this problem: it accelerates fine until it warms up, then if i step on it to pass someone or merge onto the interstate, it falls on its face somewhere between 3 and 4000 rpms. it does the same if i set the cruise on a 70 mph highway and encounter a hill. it seems to be getting worse. the plugs arent new, but i inspected all 6 and they look good. i also know they have around 20k highway miles on them. i tested the coil and found a bad post, so i replaced it with no change in the symptoms. i also just changed the fuel filter a couple days ago...no change there either. theres no engine light on, ive been thinking of unplugging a sensor just to turn it on so advance will scan the codes. so ive got a rough idle (which doesnt really bother me) and a hard stall under heavy acceleration when warm. any ideas?

try your spark plug wires, had the same issue and it fixed it right away

With no check engine light, I would check for leaks (air intake, vacuum, voltage). Some leaks may only show up when the motor is warm. Are you having oiling problems? Is there a rust colored dust around the cam sync?

update:
Changed the plugs and wires..didn't fix the problem, but got +1 mpg's afterwards.
Replaced the cam synchronizer and sensor...Voila! Fixed!
Sooo...the cam sync can be the problem even if it DOESN'T chirp.
Thanks all for the advice.

Side note: The cam sync Did squeak when I had it out in my hands, but never heard anything while it was in the truck. There was also rust dust in the cam sensor, but I attributed that to 185,000 miles of service.

update: Changed the plugs and wires..didn't fix the problem, but got +1 mpg's afterwards. Replaced the cam synchronizer and sensor...Voila! Fixed! Sooo...the cam sync can be the problem even if it DOESN'T chirp. Thanks all for the advice. Side note: The cam sync Did squeak when I had it out in my hands, but never heard anything while it was in the truck. There was also rust dust in the cam sensor, but I attributed that to 185,000 miles of service.

Yep.

----------

Quote:

Originally Posted by GLH

With that many miles on the engine, the cam sync should be changed just as preventive maintenance.